The present invention relates to a device for chemical wet treatment of substrates in a tank containing a treatment fluid, with a lifting apparatus for introducing and removing at least one substrate carrier and the substrates, as well as a drying method which uses such a lifting device.
At present, an automatic wet treatment device comprises a number of containers or tanks for a sequence of chemical wet processes. After completion of a chemical process sequence or between process steps, substrates, for example, silicone wafers arranged in a cassette, are submerged into a rinsing tank and subsequently dried.
The drying of a substrate can, for example, be performed with a centrifuge, but also during the slow removal of the substrate from the rinsing tank.
From European document 0 385 536 a drying method is known in which, in addition to the slow removal of the substrate, a vapor originating from a bath is applied to the substrate whereby the vapor does not condense on the substrate but diffuses into the liquid. At the liquid meniscus on the substrate surface a concentration gradient is produced, and thus a surface tension gradient, which causes the movement of the liquid away from the substrate into the liquid and thus results in the drying of the substrate without residue. During the chemical wet treatment, respectively, the rinsing and drying, the substrates are secured in carriers, also called wafer cassettes, in slots which are formed on the inner surface of the sidewalls of the cassette. Such standard carriers especially have relatively large surfaces with edges and corners so that a relatively large amount of chemicals is transferred from one process tank into another, respectively from one bath into another, thus making the drying process more difficult. The edges and great surface areas of conventional carriers prolong especially the respective cleaning, rinsing, and drying steps during the treatment because relatively large amounts of liquid adhere to the surfaces, edges and corners and the removal of chemicals by rinsing is more complicated. However, when the carrier does not have lateral guides, there are no lateral guides provided for the substrates during lifting. In the known devices the lateral carrier guides are used to secure the substrates during lifting from the bath in order to protect the substrates during lifting from the carrier against tipping over.
From Japanese document 5-27 06 60 (A) a device of the aforementioned kind is known in which a lifting device with a transport carriage for introducing and removing the substrates and substrate carrier into and from a container for chemical wet treatment is provided. As in the case of introduction and removal disclosed in connection with the arrangement of European document 0 385 536 A, the substrates remain within the carrier so as to be removed and introduced together with the carrier.
From U.S. Pat. No. 5,299,901 a substrate handling device is known in which a first transport carriage moves a carrier for the substrates and a second transport carrier moves the substrate into and out of the carrier. The introduction and removal of the substrates, respectively, the substrates carriers into and from a container for chemical wet treatment of substrates and the associated requirements and difficulties are not discussed in this document.
From U.S. Pat. No. 4,963,069 a substrate handling device is known in which a substrate carrier is moved up and down with a lifting apparatus and, in addition, a piston-cylinder unit with a jointed connection to the lifting rod is provided in order to disengage the substrate carrier from the lifting movement.
From German Patent 34 25 267 a device for transporting and individually handling substrates is known according to which the substrates within the substrate carrier can be lifted and the substrates can also be lifted out of the carrier.
U.S. Pat. No. 3,493,093 shows and discloses a transporting and handling device with which objects can be lifted and transported whereby a control curve is used.
It is an object of the invention to provide a device, respectively, a method for the chemical wet treatment, especially for a rinsing and/or drying, with which a continuous and secure lifting, respectively, lowering of the substrates is possible.